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Unipolar Electrogram Characteristics Predictive of Successful Radiofrequency Catheter Ablation of Accessory Pathways
Author(s) -
BARLOW MALCOLM A.,
KLEIN GEORGE J.,
SIMPSON CHRISTOPHER S.,
MURGATROYD FRANCIS D.,
YEE RAYMOND,
KRAHN ANDREW D.,
SKANES ALLAN C.
Publication year - 2000
Publication title -
journal of cardiovascular electrophysiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.193
H-Index - 138
eISSN - 1540-8167
pISSN - 1045-3873
DOI - 10.1111/j.1540-8167.2000.tb00313.x
Subject(s) - medicine , ablation , cardiology , catheter ablation , radiofrequency ablation
Unipolar Electrogram in Ablation. Introduction: The purpose of this study was to determine the characteristics of the unipolar electrogram that are most helpful in predicting successful radiofrequency ablation of accessory pathways. Methods and Results : The unipolar electrogram was analyzed at 185 ablation sites in 53 patients; 94 attempts were directed at the site of earliest atrial activation (“atrial gronp”) and 91 at the site of earliest ventricular activation (“ventricular group”). The electrogram was analyzed for several features, including pattern (“QS” or “initial R”). Unipolar pattern: Overall, a “QS” pattern was seen at 55% of unsuccessful, 75% of temporarily successful, and 90% of permanently successful sites. For the atrial group, the respective frequencies were 53%, 77%, and 92%, and for the ventricular group, 57%, 73%, and 86%. The difference in pattern distribution between unsuccessful and permanently successful sites was significant for all groups: overall, P < 0.0001; atrial group, P = 0.0005; ventricular group, P = 0.02. Absence of a “QS” pattern (i.e., “initial R”) predicted a 92% chance of unsuccessful ablation. Additional features: Activation times were significantly shorter at permanently successful than at unsuccessful (P < 0.0001) or temporarily successful sites (P = 0.0002). No significant differences were found in atrial or ventricular amplitudes or in A/V ratios. Intrinsic deflection slew was lower at temporarily successful sites (P = 0.03 vs all other sites). Conclusion: Ablation at sites revealing an “initial R” pattern (i.e., absent “QS”) is very unlikely to be successful. Activation time is shorter at successful sites. These features are equally applicable when mapping the atrial potential as when mapping the ventricular potential.